6 quarts popped corn in large roasting pan sprayed w/Pam
2 cups brown sugar
2 sticks margarine
1/2 cup Karo white syrup
1 teaspoon butter flavoring
1 teaspoon baking soda 

Mix together sugar, margarine, Karo, and salt in a pan and boil for 5 minutes. Remove from stove. Add soda and butter flavoring. Pour over corn. Place in 200 degree oven for one hour, stirring every 15 minutes.